Problem: $\sum\limits_{n=0}^{2 }{{(n)}}=$
Explanation: What is the question asking for? $\sum$ tells us to find the sum. The question is asking for the sum of the values of $n$ from $n = 0$ to $n = 2$. Evaluating $\begin{aligned} \sum\limits_{n=0}^{2 }{({n})}&= (0) + (1) + (2) \\\\ &= 0 + 1 + 2 \\\\ &= 3\end{aligned}$ The answer $\sum\limits_{n=0}^{2 }{({n})}=3$